The share of Hispanic students in the testing group rose to 17 percent in the class of 2017, up 1 percentage point from a year ago and 3 points since 2013.

The ACT analyzed how those students performed relative to benchmark scores for readiness on the test's four sections. A flawless score is 36.

The ACT's new web-based testing platform hit some snags in SC in February and March, when students saw their computer and tablet screens freeze as the testing timer ticked on.

"While we have made progress over the past year, we have significant ground to cover in order to meet our goal that every student graduates prepared for success", she added.

Beginning this school year, the ACT and SAT tests replace end-of-instruction exams and will be required for all 11th grade students.

The decline happened largely because IL and MI, two big states that require students to take a statewide college-entrance test, switched from the ACT to the Saturday.

Officials highlighted the performance of what they called "underserved" populations, those who would be the first generation in their family to attend college, come from low-income families or self-identify their race or ethnicity as a minority.

Oklahoma met only one benchmark score, the 18 benchmark in English. The ACT is different from the SAT because it focuses on academic achievement and mastery of the skills and knowledge students are taught in school. Nationwide, 60 percent took the test.

"While it's no surprise that underserved students fall behind their peers due to the inequities that exist, it's extremely alarming and concerning to see how large this achievement gap really is", said ACT Chief Executive Officer Marten Roorda. Six in 10 Asian-American students and half of white students met those benchmarks.

Black test-takers trailed all racial groups in both states. ACT says just 28 percent of Nebraska students met the benchmarks in all four areas, compared with 27 percent nationally. The benchmarks predict a 50 percent chance the student will obtain a B or higher or a 75 percent chance of earning a C or higher in the corresponding college course. Fifty-five percent of Vermont students were prepared in science versus 31 percent nationally.

Some states with the highest average composite scores have limited participation, in part because students opt to take the Saturday.